"I would really like to be able to play with OpenBSD's PF, or FreeBSD's jail, but I'm rather fond of Gentoo and portage. Right now anybody wanting to play with portage on a BSD has a lot of work to do before getting started, since we don't have stage-1 tarballs. I still don't have a stage-1, but this text and attendent files comprises a small start along the road to generating one." Read the instructions here.